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Posted at 5:00 AM ET, 02/ 7/2008

Forecast: Turning Cooler One Day at a Time

By Josh Larson

Highs in the 50s today; Feeling like the teens by Sunday.

It's the mark of a truly mild pattern when temperatures behind a cold front are still as much as 10 degrees above normal. Highs are bound for the low to mid 50s today -- safely above the average of mid 40s -- in the wake of a cold front that pushed through last night, triggering evening showers and thunderstorms and closing the book on yesterday's record highs in the low 70s. Gradually, temperatures will turn cooler and eventually downright cold, with highs in the 40s on Saturday and in the 30s on Sunday with a biting wind that could produce wind chills in the teens.

TODAY

Sun and clouds, low to mid 50s. Behind yesterday's cold front, it will be quite breezy with winds out of the northwest at 15-20 mph, gusting to 30 mph at times. High temperatures will max out in the low to mid 50s in most spots as skies feature some clouds but also a good amount of sun. Mostly clear and colder overnight, with lows ranging from the upper 20s to near 30 in suburban spots like Herndon and Gaithersburg to near 35 downtown.

TOMORROW

Mostly sunny, near 50. Friday should bring partly sunny skies along with lighter winds. Afternoon highs will probably be within a couple degrees of 50. A weak disturbance may allow for increasing clouds Friday night, which would keep overnight lows in the upper 30s downtown to near freezing across the coolest suburbs.

Keep reading for the forecast through the weekend as well as a sneak peek at early next week. And check back later this morning for Andrew Freedman's take on the Super Tuesday tornado outbreak.

THE WEEKEND

Upper 40s Saturday; near freezing Sunday. This upcoming weekend will be one of noticeable transition as temperatures drop from slightly above normal levels on Saturday to much below normal on Saturday, courtesy a strong cold front which is likely to push through late in the day Saturday.

Expect more clouds than sun on Saturday, with a stray shower possible and highs in the upper 40s. Saturday night will feature mostly cloudy skies with a chance of snow showers and lows ranging from the mid 20s to low 30s. Then, dramatically colder on Sunday with high temperatures struggling to reach the freezing mark, despite mostly sunny skies, and wind chills spending much of the day in the teens thanks to winds that could reach sustained speeds of 20-30 mph. Clear and very cold Sunday night, with lows ranging from the low to mid teens in places like McLean and Damascus to near 20 downtown.

A LOOK AHEAD

Prepare for mostly sunny conditions on Monday, with chilly highs in the low to mid 30s and overnight lows from the mid to upper teens across the coolest spots to the low 20s downtown.

Slightly milder temperatures are expected on Tuesday, with highs approaching or surpassing 40 and overnight lows predominately in the 20s to near 30.

Seasonable temperatures along with partly sunny conditions can be expected on Wednesday, with highs in the mid 40s and overnight lows from 25-30.

By Josh Larson  | February 7, 2008; 5:00 AM ET
Categories:  Forecasts  
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Next: Freedman: Super Tuesday Spin

Comments

What happened to make yesterday's forecast such a bust? Forecasted rain chances were 80-100%, with predictions of heavy rains starting during the late afternoon. Yet, the only thing I saw in Arlington other than a few sprinkles was a short-lived band that came through at about 11 PM. As a bicycle commuter, the forecast almost made me drive to work yesterday, but I'm glad I ignored the forecast and rode my bike anyway, as I had nice warm and dry conditions both morning and evening. Heck, the sun was out for much of the ride home.

Posted by: Al | February 7, 2008 8:34 AM | Report abuse

Al: Here is what Dan's forecast from yesterday said "...there's a 30-40 percent chance of showers in the afternoon, and then a better chance (more like 60 percent) of showers and thunderstorms during the evening hours." The CommuteCast said showers were likely, and maybe some t'storms. Both of these forecasts were more or less right, although the accompanying text may have overstated the risk of heavy rain and severe storms. But we had to err on the side of caution given the storm's history. You raise a fair point that maybe the forecast focus was misplaced since other than the brief showers and t'storms, most of the evening was pretty nice. Note though, we never said it would rain the whole time. The bottom line is that forecasting convective storms and communicating their impacts is a bit tricky...they can be hit or miss and are usually short-lived in nature. We'll try and do a better job communicating the next time.

Posted by: Jason, Capital Weather Gang | February 7, 2008 9:40 AM | Report abuse

In support of Al's post: The real-time forecast was a bust. They were evidently expecting something like the huge tornado outbreak west of the Appalachians. I even saw a "moderate" risk of severe weather posted at one point. Instead, yesterday evening commute was dry. I was able to shop the Ballston Harris Teeter after work. The convective activity rolled through just before 11 PM, but was nothing like the outbreak west of the mountains and south of the Ohio River the day before. Probable explanation: The passage over the Appalachian Mountains most likely served to dampen the atmospheric instability within the system. (Shouldn't model guidance have caught onto this during the analysis process?)

Evidently there is a problem with real-time analysis of the parameters generally associated with severe weather. These parameters, which include: CAPE, Lifted Index, Helicity, Bulk Richardson Number, Cross Totals, Total Totals, and probably a couple of additional parameters, are generally determined from a couple of radiosonde balloon launches per day from certain NOAA-designated airports (I believe that Dulles [IAD] is the airport in this area!). I'm not sure whether the standard models everyone uses monitor the rates of change in these factors on a continuing basis. (I believe that BUFKIT analysis often catches changes in severe weather factors.) What's probably needed may not be within our technological capability at this time. This would probably take the form of a continuous real-time monitoring of the seven or eight important severe-weather related parameters by a method other than twice-daily weather balloon launch. The best bet would be a way of evaluating these factors through Doppler radar analysis. The best way of implementing a NEXRAD-plus Doppler radar system is certainly within our grasp in the near future. All that would be needed is to integrate the current NOAA NEXRAD system with all the TV-station Doppler Radars into a nationwide NEXRAD-Plus radar network. Such a move would likely cost less than the launching of a new geostationary weather satellite. I don't know why it hasn't yet been proposed.

Posted by: El Bombo | February 7, 2008 10:10 AM | Report abuse

Thanks Jason ... Yes, Al (and even El Bombo), you seem to be referring to forecasts other than ours. We gladly take blame when we miss a forecast, but our forecasts yesterday were mostly on target. And as Jason pointed out, the morning forecast had a farily low percent chance of anything for the afternoon, with a 60% chance for the evening when a line of showers and storms did impact a good portion of the region. Not only that, but if anything we underplayed the severe threat in both the morning forecast and CommuteCast. This wasn't by accident. We didn't feel like the severe threat was quite as significant as other sources may have.

Posted by: Dan, Capital Weather Gang | February 7, 2008 10:31 AM | Report abuse

The Cap. Wea. Gang usually produces an excellent product regarding precip. events. This is great, considering their budget compared to the NWS!!

The NWS is not in the same league, especially the Sterling office which of course covers most of our area. My constant comparison reveals the Blacksburg office to usually be more accurate for my area. Augusta/Rockbridge counties separate the Sterling/Blacksburg jurisdiction. The majority of the time Sterling is consistent in overstating both P.O.P. and Q.P.F. for my area, also inaccuracy re. beginning and ending times of events.

The models have also had a "bullish" bias regarding QP potential beyond 24 hrs. since the premature collapse of El Nino more than a year ago.

The CPC released their latest ENSO discussion this morning. The La Nina conditions are expected to persist through the spring, resulting in continued below normal precip. for the southeastern U.S. Region 3.4 was around -1.8 at the end of Jan. with some of the equatorial Pacific being more than -2.0. Their spaghetti model suite suggests perhaps neutral conditions by fall.

Posted by: Augusta Jim | February 7, 2008 11:43 AM | Report abuse

Most outlets are calling for highs in the mid-30s to around 40 on Sunday, and low 40s on Monday. In my 20 years of living here, cold temps often are moderated somewhat before they reach here. So I would guess temps will be warmer than you are estimating by at least a few degrees.

Posted by: steve takoma park mdz7 | February 7, 2008 11:48 AM | Report abuse

... leading to permanent drought conditions and developing desertification in the southeast??

Posted by: wsl | February 7, 2008 12:06 PM | Report abuse

The 12z GFS has some interesting ideas at 156 hrs. regarding a possible wintry event. The 00z from yesterday also liked this idea but the 06z backed off, keeping us on the warm side of the system, now we go cold again.

In 'Dreamland" at 300 hrs. the GFS also now likes the idea of a significant Winter Storm. Snowlovers, DON'T GIVE UP HOPE !!!

Posted by: Augusta Jim | February 7, 2008 12:13 PM | Report abuse

:)

Posted by: missy | February 7, 2008 12:46 PM | Report abuse

This may come as a surprise to many in this area. Last month was colder than normal over the United States, based on records going back 114 years (1895-2008), averaging 30.50F, compared to 39.52F two years ago in 2006. The 20th century average was 30.2.
http://www.ncdc.noaa.gov/oa/climate/research/cag3/na.html

Posted by: Augusta Jim | February 7, 2008 1:50 PM | Report abuse

I was similarly misled, Al, but not by CapWx. I understood it to be a near-certainty we would have strong pm thunderstorms based on the WTOP forecasts Tues. night and Wed. morning.

Posted by: Mark | February 7, 2008 2:24 PM | Report abuse

Augusta Jim,

"Dreamland" 300 hr = President's Day. Coincidence?

Posted by: Jamie C in Chevy Chase | February 7, 2008 2:59 PM | Report abuse

It may have been colder across most of the US, but in this area since Dec 20 the temps have averaged 6.6 above, with 43 of last 50 above. Models 300 hrs out r as accurate as throwing at a dart board, now if it's still showing something less than 72 hrs out, then it's worth watching.

Posted by: VaTechBob. | February 7, 2008 3:10 PM | Report abuse

Yes, I wasn't referring to the Weather Gang forecast, but the ones on the TV, weather channel, and NWS. I did not the weather gang one was better.

Al

Posted by: Al | February 7, 2008 4:24 PM | Report abuse

VT Bob:
Thats why I call anything beyond 7 days, "Dreamland". It will almost certainly change,or disappear, but it's nice for snowlovers to dream about.

Posted by: Augusta Jim | February 7, 2008 5:00 PM | Report abuse

The comments to this entry are closed.

 
 
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